The present invention relates to a sealing arrangement between the shaft carrying at least a rotor and the housing of a fluid flow engine or jet engine comprising two sealing places arranged at an axial distance from one another which delimit a blocking gas space acted upon with blocking gas and includes at least one sealing place consisting of a sealing ring inserted into an annular groove of the shaft and radially sealingly abutting against the shaft through-bore.
The purpose of such a sealing arrangement, in which the sealing ring that does not move in the circumferential direction, results in conjunction with the coordinated annular groove in the rotating shaft in a labyrinth seal, is to prevent lubricating oil losses out of the bearing places of the shaft and the overflow of hot gases out of the rotor space into the bearing places.
A sealing arrangement of the aforementioned type is disclosed in the DE 32 19 127 C2 in which one sealing ring is pressed by the excess pressure in the blocking gas space against the lateral flank of its annular groove opposite the rotor. After an initial wear at the sealing ring with respect to the annular groove-lateral flank, the sealing ring is displaced against the right angle step in the bore for the passage of the shaft. The wear at the sealing ring thereby comes to a standstill.
The sealing ring delimiting the blocking gas space in the direction to the rotor space is in the normal case axially in equilibrium between the pressure in the blocking gas space and the gas pressure in the rotor space without contact of one of the lateral flanks of the annular groove so that no annular wear occurs.
In case of a failure or defective functioning of the blocking gas pressure supply, the sealing ring adjacent the rotor space is displaced by the gas pressure prevailing in the rotor space axially toward the blocking gas space and abuts at the lateral flank of the annular groove. As an axial abutment for the sealing ring is missing in the through-bore for the shaft, this failure or defective functioning leads to an operation-endangering wear up to the total loss of the sealing ring.
It is therefore the object of the present invention to provide a sealing arrangement for the delimitation of a blocking gas space between the shaft and the housing of a fluid flow engine or jet engine in which a wear of the sealing rings endangering the operation is avoided, and which is insensitive to failure or defective functioning of the blocking gas pressure supply.
The underlying problems are solved according to the present invention in that the through-bore for the shaft includes three diameter regions mutually offset by two right angle steps, in that the first step between the small and a middle diameter region is coordinated to the one sealing ring, in that the second step between the middle and a large diameter region is coordinated to the other sealing ring and in that the annular groove for the sealing ring coordinated to the first step is formed between a shoulder of the shaft and a ring adapted to be slipped over the shaft.
The advantages achieved with the present invention reside in particular in that a support at a step of the through-bore for the shaft is also created for the sealing ring on the side of the rotor so that this sealing ring is protected against total wear endangering the operation in case of insufficient blocking gas pressure, in that a non-complicated installation of the sealing arrangement results and in that the sealing arrangement exhibits an improved insensitivity with respect to an alternating blocking gas pressure.